Media content receivers, such as satellite and cable television broadcast receivers or set-top boxes (STBs), may facilitate access to literally hundreds of television programming channels provided for subscribers of a television broadcasting service. In the case of satellite television receivers, one or more satellite uplink facilities receive programming from several different content sources, such as major broadcast networks, independent television stations, and the like. The uplink facility then transmits this programming over wireless uplink communication paths to a satellite, which then broadcasts the programming over a set of wireless downlinks to the receivers.
In the case of satellite television broadcast systems, the uplink center often encrypts multiple channels of the transmitted programming to prevent reception of those channels by receivers that are not authorized to access that programming. For example, some of the channels may be available to all subscribers of a particular programming service, while other channels may be premium channels requiring an additional payment from the subscriber for access thereto. As a result, a receiver authorized to receive and display certain channels for a subscriber must be configured with one or more programming decryption keys to decrypt those channels the set-top box is authorized to receive. To this end, a removable circuit device (sometimes referred to as a “smart card”) that contains the necessary programming decryption keys, algorithms, or circuitry, as well as other information related to a particular programming service subscriber, may be installed in each of the receivers to facilitate access to the programming authorized for a particular user subscription.
Over time, television service “pirates” attempting to gain unauthorized access to the programming may discover the necessary decryption keys and algorithms to decrypt the programming. In an effort to counter this piracy, the programming service provider may periodically change the decryption keys by way of communications directed to each of the installed removable circuit devices over the same communication path carrying the programming to the satellite television receivers. Since each receiver may be authorized to access a different set of programming channels, at least some programming decryption keys may be directed to specific receivers. To that end, each of the removable circuit devices is associated with a unique address so that messages containing the programming decryption keys may be sent to targeted smart cards by way of their address. Each receiver is thus configured to receive and process only those messages that are addressed to its installed removable circuit device. Further, the uplink facility often exploits this addressing capability of the removable circuit device to transmit other information, such as user text messages and control commands, to both the removable circuit device and the associated receiver.
To further thwart the efforts of programming pirates, the programming service may periodically replace currently-installed removable circuit devices, or smart cards, with newer, more sophisticated devices, thus making piracy more difficult. Ordinarily, the programming service sends the newer cards to the subscribers and instructs the subscriber to replace the older removable circuit devices with the newer cards so that the subscriber may continue to enjoy the programming to which the subscriber is entitled.